[Solixious]

Here is a snippet code which can perform Port Scanning of your localhost or the host you pass as argument.

Code:

import java.net.*;
import java.io.*;
public class PortScanner
{
    public static void main(String[] args)
    {
        String host = "localhost";
        if (args.length > 0)
        {
            host = args[0];
        }    
        for (int i = 1; i < 1024; i++)
        {
            try
            {
                Socket s = new Socket(host, i);
                System.out.println("There is a server on port " + i + " of "+ host);    
            }
            catch (UnknownHostException ex)
            {
                System.err.println(ex);
                break;
            }
            catch (IOException ex)
            {
                ex.printStackTrace();
            }
        } // end for
    } // end main
} // end PortScanner

[Solixious]

Here is a snippet code which can perform Port Scanning of your localhost or the host you pass as argument.

Code:

import java.net.*;
import java.io.*;
public class PortScanner
{
    public static void main(String[] args)
    {
        String host = "localhost";
        if (args.length > 0)
        {
            host = args[0];
        }    
        for (int i = 1; i < 1024; i++)
        {
            try
            {
                Socket s = new Socket(host, i);
                System.out.println("There is a server on port " + i + " of "+ host);    
            }
            catch (UnknownHostException ex)
            {
                System.err.println(ex);
                break;
            }
            catch (IOException ex)
            {
                ex.printStackTrace();
            }
        } // end for
    } // end main
} // end PortScanner

[the voice]

Hi... this is a simple evolution of your scanner

Code:

import java.io.IOException;
import java.net.Inet4Address;
import java.net.InetAddress;
import java.net.Socket;
import java.net.UnknownHostException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class PScan {

    protected final static int MAX_PORTS = (int)Character.MAX_VALUE;
    protected static InetAddress TARGET;
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        String host = (args.length == 1)? args[0] : "localhost";
        try{
            TARGET = Inet4Address.getByName(host);
        }catch(UnknownHostException uh){
            System.out.println("Unknow Host --> "+host);
            System.exit(-1);
        }
        ExecutorService exs =
                Executors.newFixedThreadPool(Runtime.getRuntime().availableProcessors() + 1);
        System.out.println("Scanning host " + TARGET.getHostAddress());
        for(int i = 1; i <= MAX_PORTS; i++){
            exs.submit(new Scan(i));
        }
        exs.shutdown();
    }
}
class Scan implements Runnable{
    
    private int port_number;
    
    public Scan(int pn){this.port_number = pn;}
    
    public void run(){
        Socket sock = null;
        try{
            sock = new Socket(PScan.TARGET, port_number);
            System.out.println("The port "+port_number+" is open");
        }catch(IOException ioe){
            
        }
        if(port_number == PScan.MAX_PORTS){
            System.out.println("Last port reached");
        }
    }
}

It's a simple multithreading scanner.